Aging as a window into central auditory dysfunction: Combining behavioral and electrophysiological approaches

Abstract

Central auditory processing involves a complex set of feed-forward and feedback processes governed by a cascade of dynamic neuro-chemical mechanisms. Central auditory dysfunction can arise from disruption of one or more of these processes. With hearing loss, dysfunction may begin with reduced and/or altered input to the central auditory system followed by peripherally induced central plasticity. Similar central changes may occur with advancing age and neurological disorders even in the absence of hearing loss. Understanding the behavioral and physiological consequences of this plasticity on the processing of basic acoustic features is critical for effective clinical management. Major central auditory processing deficits include reduced temporal processing, impaired binaural hearing, and altered coding of spectro-temporal features. These basic deficits are thought to be primary contributing factors to the common complaint of difficulty understanding speech in noisy environments in persons with hearing loss, brain injury, and advanced age. The results of investigations of temporal, spectral, and spectro-temporal processing, binaural hearing, and loudness perception will be presented with a focus on central auditory deficits that occur with advancing age and hearing loss. Such deficits can be tied to reduced peripheral input, altered central coding, and complex changes in cortical representations.